1. Field of the Invention
The present invention pertains to an apparatus which may be inserted in a wellbore and operated to provide a barrier between the well and perforations in the wellbore casing so that fracturing or other wellbore operations may be carried out at intervals either above or below the blocked perforations.
2. Background
In certain wellbore operations, where the well casing has already been perforated at a particular zone in an earth formation, it is sometimes desired to block these perforations, either permanently or on a temporary basis, while wellbore operations are carried out at intervals either above or below the interval which is to be blocked from communicating with the well. For example, when it is desired to perform certain stimulation techniques such as fracture initiation or extension into an earth formation zone below a zone which has already been placed in communication with the well by wellbore casing perforations, it is difficult to block off the upper set of perforations while the fracturing or other stimulation technique is carried out in the lower zone.
However, the present invention provides a unique apparatus and method for permanently or temporarily blocking a set of casing perforations to prevent communication between the wellbore and an earth formation adjacent the perforations.